JP4090127B2 - Optical recording material - Google Patents

Description

（式中、ｎは１〜３の整数を表し、ｍは０または１の整数を表し、６員環Ａはベンゼン環またはシクロヘキサン環を表し、Ｘは炭素原子数１〜３のアルキレン基を表し、Ａｎ^-はアニオンを表す。ｍが０のとき、Ｒ₁およびＲ₂は各々独立に、水素原子、ハロゲン原子または炭素原子数１〜８のアルキル基、アルコキシ基、アルケニル基もしくはアルケニルオキシ基を表し、ｍが１のとき、Ｒ₁はハロゲン原子または炭素原子数１〜８のアルコキシ基もしくはアルケニルオキシ基を表し、Ｒ₂は水素原子、ハロゲン原子または炭素原子数１〜８のアルコキシ基もしくはアルケニルオキシ基を表す。ただし、ｎが１かつｍが１のとき、Ｒ ₁ またはＲ ₂ がハロゲン原子である場合を除く。）
【００１９】
【発明の実施の形態】
以下、本発明の光学記録材料についてさらに詳細に説明する。
【００２０】
本発明に係る上記一般式（Ｉ）で表される化合物は、光学記録媒体の記録層に使用される色素である。
【００２１】
上記一般式（Ｉ）で表される化合物において、Ｒ₁ およびＲ₂ で表される炭素原子数１〜８のアルキル基としては、例えば、メチル、エチル、プロピル、イソプロピル、ブチル、第二ブチル、第三ブチル、イソブチル、アミル、第三アミル、ヘキシル、ヘプチル、オクチル、イソオクチル、第三オクチル、２−エチルヘキシルなどが挙げられ、炭素原子数１〜８のアルコキシ基としては、上記アルキル基から誘導される基が挙げられ、炭素原子数１〜８のアルケニル基としては、例えば、ビニル、プロペニル、イソプロペニル、ブテニルなどが挙げられ、炭素原子数１〜８のアルケニルオキシ基としては、上記アルケニル基から誘導される基が挙げられ、また、ハロゲン原子としては、フッ素、塩素、臭素、ヨウ素などが挙げられる。
また、Ｘで表される炭素原子数１〜３のアルキレン基としては、例えば、メチレン，エチレン、トリメチレンなどが挙げられる。
【００２２】
また、Ａｎ^- で表されるアニオンとしては、例えば、塩素アニオン、臭素アニオン、ヨウ素アニオン、フッ素アニオンなどのハロゲンアニオン；過塩素酸アニオン、チオシアン酸アニオン、六フッ化リンアニオン、六フッ化アンチモンアニオン、四フッ化ホウ素アニオンなどの無機系アニオン、または、ベンゼンスルホン酸アニオン、トルエンスルホン酸アニオン、トリフルオロメタンスルホン酸アニオンなどの有機スルホン酸アニオン；オクチルリン酸アニオン、ドデシルリン酸アニオン、オクタデシルリン酸アニオン、フェニルリン酸アニオン、ノニルフェニルリン酸アニオンなどの有機リン酸アニオンなどの有機系アニオン、あるいは、例えば、クエンチャーアニオンとして、特開昭６０−２３４８９２号公報に記載されたようなアニオンが挙げられる。該クエンチャーアニオンの代表例としては、下記〔化３〕の一般式（Ａ）および（Ｂ）で表されるアニオンが挙げられる。
【００２３】
【化３】

【００２４】
また、ｎは１〜３の整数を示すが、特にｎが１である化合物が、書き込みおよび再生の６２０〜６９０ｎｍの波長に対して感度に優れるため好ましい。
【００２５】
上記一般式（Ｉ）で表される化合物のうち、特に、Ｒ₁ およびＲ₂ の少なくとも一方がハロゲン原子である化合物、Ｒ₁ およびＲ₂ の少なくとも一方がアルコキシ基である化合物、またはＲ₁ およびＲ₂ の少なくとも一方がアルケニルオキシ基である化合物が好ましい。
【００２６】
上記一般式（Ｉ）で表される化合物の代表例としては、下記化合物Ｎｏ．１〜５などが挙げられる。以下の例示では、アニオンを省いたシアニン色素カチオンで示している。なお、下記化合物のうち、化合物Ｎｏ．４は参考化合物である。
【００２７】
【化４】

【００２８】
【化５】

【００２９】
【化６】

【００３０】
【化７】

【００３１】
【化８】

【００３２】
上記一般式（Ｉ）で表される化合物からなる本発明の光学記録材料は、上記シアニン色素カチオンとアニオンとの塩であり、従来周知の方法に準じて製造することができる。
【００３３】
次に、上記一般式（Ｉ）で表される化合物の具体的な合成例を挙げる。
【００３４】
（合成例１）化合物Ｎｏ．１の過塩素酸塩の合成
温度計、冷却管、窒素導入管つき丸底５００ｍｌフラスコに、４−ヒドロキシフェネチルアルコール４８．４ｇ、ＫＯＨ３９．３ｇ、エタノール７８．９ｇを仕込み、７０℃に加温した。そこへアリルブロマイド４６．６ｇを９０分かけて滴下した後、８０℃で１時間反応させた。冷却後、溶媒を留去し、残留物をトルエン２００ｍｌに溶解させ、水２００ｍｌで４回、水洗と油水分離を繰り返した。有機層を取り、溶媒を留去して、第一中間体である、４−アリロキシフェネチルアルコール４１．６ｇ（無色透明液体、収率６６．８％）を得た。
【００３５】
得られた４−アリロキシフェネチルアルコール２６．７ｇ、ピリジン２９．７ｇを仕込み、０〜１０℃で撹拌しながらベンゼンスルホン酸クロライド２６．５ｇを滴下した。この温度のまま１時間撹拌し、さらに室温で１時間撹拌した。次に、クロロホルム１００ｍｌを加えて溶解し、水１００ｍｌで２回水洗と油水分離を行った。有機層を取り、溶媒を留去して、第二中間体である、４−アリロキシフェネチルベンゼンスルホネート４０．５ｇ（無色透明液体、収率８４．７％）を得た。
【００３６】
得られた４−アリロキシフェネチルベンゼンスルホネート１５．９ｇ、２，３，３−トリメチル−５−ニトロインドレニン５．１ｇを仕込み、１３５〜１４０℃で１時間反応させ、第三中間体である１−（４' −アリロキシフェネチル）−２，３，３−トリメチル−５−ニトロインドレニンのベンゼンスルホン酸塩を得た。この反応物は、精製せず次の工程にそのまま使用した。
【００３７】
上記反応物、Ｎ，Ｎ−ジフェニルホルムアミド０．７３ｇ、ピリジン１１．９ｇ、無水酢酸１．９ｇを仕込み、１１５℃で１時間反応させた。次に、過塩素酸ナトリウム・１水和物３．９ｇ、メタノール１９．３ｇを加え、メタノール還流下で１時間反応させた。溶媒を留去した後、ＤＭＦ／メタノール＝１／３の混合溶媒から再結晶を行い、化合物Ｎｏ．１の過塩素酸塩（緑色結晶）２．５ｇを得た。
【００３８】
得られた結晶の光学的特性として次の結果を得た。
・λmax （クロロホルム溶液、以下同じ）＝５８７．０ｎｍ
・ε（λmax におけるモル吸光係数、以下同じ）＝２．０４×１０⁵
【００３９】
上記（合成例１）と同様に、化合物Ｎｏ．２〜５の過塩素酸塩を合成し、各化合物についてλmax およびεを測定した。それらの結果を下記〔表１〕に示す。
【００４０】
【表１】

【００４１】
本発明の光学記録材料は、光学記録媒体の記録層として適用される。これにより、基体上に、上記一般式（Ｉ）で表される化合物からなる薄膜を形成した光学記録媒体を提供することができる。
上記光学記録媒体の形成にあたっては従来周知の方法を用いることができる。一般には、メタノール、エタノール、などの低級アルコール類、メチルセロソルブ、エチルセロソルブ、ブチルセロソルブ、ブチルジグリコールなどのエーテルアルコール類、アセトン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン、ジアセトンアルコールなどのケトン類、酢酸エチル、酢酸ブチル、酢酸メトキシエチルなどのエステル類、アクリル酸エチル、アクリル酸ブチルなどのアクリル酸エステル類、２，２，３，３−テトラフルオロプロパノールなどのフッ化アルコール類、ベンゼン、トルエン、キシレンなどの炭化水素類、メチレンジクロライド、ジクロロエタン、クロロホルムなどの塩素化炭化水素類などの有機溶媒に、本発明の光学記録材料を溶解した溶液を基体上に塗布することによって容易に光学記録媒体を形成することができる。
【００４２】
上記記録層の厚さは、通常、０．００１〜１０μであり、好ましくは０．０１〜５μの範囲が適当である。上記記録層の形成方法は特に制限を受けず、例えばスピンコート法などの通常用いられる方法を用いることができる。
【００４３】
本発明の光学記録材料を、光学記録媒体の記録層に含有させる際の該記録層に対する使用量は、好ましくは５０〜１００重量％である。
【００４４】
また、上記記録層は、本発明の光学記録材料のほかに、必要に応じて、ポリエチレン、ポリエステル、ポリスチレン、ポリカーボネートなどの樹脂類を含有してもよく、界面活性剤、帯電防止剤、滑剤、難燃剤、安定剤、分散剤、酸化防止剤、架橋剤などを含有してもよい。
【００４５】
さらに、上記記録層は、一重項酸素などのクエンチャーとして芳香族ニトロソ化合物、遷移金属キレート化合物などを含有してもよい。これらの化合物としては、例えば、特開昭５９−５５７９５号公報に提案されているような公知の化合物が用いられる。該化合物は、記録層に対して好ましくは０〜５０重量％の範囲で使用される。
【００４６】
このような記録層を設層する上記基体の材質は、書き込み光および読み出し光に対して実質的に透明なものであれば特に制限はなく、例えば、ポリメチルメタクリレート、ポリエチレンテレフタレート、ポリカーボネートなどの樹脂、ガラスなどが用いられる。また、その形状は、用途に応じ、テープ、ドラム、ベルト、ディスクなどの任意の形状のものが使用できる。
【００４７】
また、上記記録層上に、金、銀、アルミニウム、銅などを用いて蒸着法あるいはスパッタリング法により反射膜を形成することもできるし、アクリル樹脂、紫外線硬化性樹脂などによる保護層を形成することもできる。
【００４８】
本発明の光学記録材料は、ＬＤ、ＣＤ、ＤＶＤ、ＣＤ−Ｒ、ＤＶＤ−Ｒなどの光ディスク用色素として使用することができ、特に書き込み再生に６２０〜６９０ｎｍの波長の光を用いるＤＶＤ−Ｒに好適である。
【００４９】
【実施例】
以下、実施例をもって本発明を更に詳細に説明する。しかしながら、本発明は以下の実施例によって何ら制限を受けるものではない。なお、以下の実施例のうち、実施例１−４、２−４及び３−４は参考例である。
【００５０】
（実施例１）
チタンキレート化合物（Ｔ−５０：日本曹達社製）を塗布、加水分解して下地層（０．０１μ）を設けた直径１２ｃｍのポリカーボネートディスク基板上に、下記〔表１〕に示す色素および芳香族ニトロソ化合物（ＤＱ−２４：旭電化工業（株）製）の１：０．１（重量比）のエチルセロソルブ溶液をスピンコーティング法にて塗布して、厚さ１００ｎｍの記録層を形成した。
【００５１】
さらに、記録層上に１００ｎｍの金の反射膜を蒸着法により形成した。
【００５２】
このようにして作成された各光学記録媒体を、３．６ｍ／ｓで回転させながら半導体レーザ（６３５ｎｍ、集光部出力７ｍＷ、周波数２ｋＨｚ）を用いて基盤裏面側から書き込みを行った。
【００５３】
次いで、半導体レーザ（６５０ｎｍ、集光部出力０．１ｍＷ）を読み出し光とし、基盤をとおしての反射光を検出してスペクトラムアナライザにて、バンド巾３０ｋＨｚでＣ／Ｎ比を測定した。
【００５４】
また、０．１ｍＷのレーザを読み出し光とし、１μ秒巾、３ｋＨｚのパルスとして、静止状態で５分間照射した後および４０℃、相対湿度８８％の条件下に２５００時間保存した後の、基盤裏面側からの反射率の変化（％）を測定した。それらの結果を下記〔表２〕に示す。
【００５５】
【表２】

【００５６】
【化９】

【００５７】
【化１０】

【００５８】
（実施例２）
下記〔表３〕に示す色素を用いて実施例１と同様に各光学記録媒体を作成し、分光エリプソメータ（Ｍ−１５０、日本分光（株）製）を用いて屈折率（ｎ）と消衰係数（ｋ）を測定した。それらの結果を下記〔表３〕に示す。
【００５９】
【表３】

【００６０】
（実施例３）
下記〔表４〕に示す色素を用いて実施例１と同様に各媒体を作成し、キセノン耐候性試験機（テーブルサン、スガ試験機（株）社製）を用いて、５００００ルクスの光を照射し、λmax における吸光度半減期（λmax における吸光度の値が、媒体作成時の５０％まで低下するのに要する時間）を測定した。それらの結果を下記〔表４〕に示す。
【００６１】
【表４】

【００６２】
上記実施例から明らかなように、本発明に係る前記一般式（Ｉ）で表される化合物を用いた場合は、従来のシアニン色素を用いた場合と比較して、書きこみ感度に優れ、照射後および保存後の反射率の低下が著しく小さく、またｎとｋのバランスが優れることから、極めて信頼性の高い記録が可能となる。
【００６３】
【発明の効果】
本発明の光学記録材料は、光安定性、保存安定性および溶媒への溶解性が良好であり、かつ感度の高いものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical recording material used for an optical recording medium for recording by applying information as a thermal information pattern by a laser or the like, and more specifically, has a wavelength in the visible and near-infrared region and has a low energy. The present invention relates to an optical recording material used for an optical recording medium capable of high-density optical recording and reproduction by a laser or the like.
[0002]
[Background Art and Problems to be Solved by the Invention]
In general, an optical recording medium has a feature that the recording medium does not wear and deteriorate because the recording head does not contact the writing or reading head. In particular, an optical recording medium that gives information as thermal information does not require development processing in a dark room. The development has been actively conducted because of its advantages.
[0003]
Such an optical recording medium uses recording light as heat. For example, information can be recorded at high density by forming optically detectable pits on a thin recording layer provided on a substrate. Can do.
[0004]
Information is written on the recording medium by scanning a laser focused on the surface of the recording layer and forming pits in the recording layer that has absorbed the irradiated laser energy. In the information recorded on this recording medium, formed pits can be detected by reading light.
[0005]
As the recording layer of such an optical recording medium, inorganic materials such as metal thin films such as aluminum vapor deposition films, tellurium oxide thin films, bismuth thin films and chalcogenide-based amorphous glass films have been mainly used so far.
[0006]
These thin films are difficult to form by a coating method and need to be formed by sputtering or vacuum vapor deposition. However, the operation is complicated, and when the above inorganic material is used, it is difficult to form a laser beam. It has drawbacks such as high reflectivity, high thermal conductivity, and low utilization efficiency of laser light.
[0007]
Therefore, a method has been proposed in which an organic compound mainly composed of a dye as an optical recording material, which can form pits with a semiconductor laser, instead of an inorganic substance, is used as a recording layer.
[0008]
As these dyes, cyanine dyes such as indolenine, thiazole, imidazole, thioxazole, quinoline, and selenazole are known. These dyes are salts of cyanine dye cations and various anions such as halogen anions and perchlorate anions. In particular, indolenine dyes are preferably used because of their high sensitivity.
[0009]
As an optical recording medium using such a dye, an optical recording medium (CD-R) which can be written and reproduced by a near-infrared semiconductor laser having a wavelength of 770 to 830 nm corresponding to the compact disc (CD) standard has been put into practical use. .
[0010]
Recently, a red semiconductor laser with a wavelength of 620 to 690 nm shorter than 770 nm has been developed, and the recording density is increased by making the beam spot smaller, and the capacity is large enough to record moving images using data compression technology. Optical recording media (digital versatility discs, DVDs) have also been developed.
[0011]
The present invention relates to a cyanine dye that is optimal for an optical recording medium (DVD-R) that can be additionally recorded or recorded in conformity with the DVD standard.
[0012]
For example, a dye used for an optical recording medium that performs writing at 635 nm and uses a wavelength of 650 nm for reading has a sensitivity for writing at 635 nm and has a high reflectance at 650 nm, that is, a large molecular extinction coefficient. Things are desirable.
[0013]
For example, Japanese Patent Application Laid-Open No. 59-55795 has proposed an optical recording medium using an indocarbocyanine dye in the recording layer as a dye compatible with writing with a red semiconductor laser of 620 to 690 nm.
[0014]
However, these dyes cannot be said to exactly match the absorption wavelength of the DVD-R standard, and the reflectance is not sufficient.
[0015]
Accordingly, an object of the present invention is to provide an optical recording material which is used for a recording layer of an optical recording medium and has good light stability, storage stability and solubility in a solvent, and has high sensitivity. is there.
[0016]
[Means for Solving the Problems]
As a result of repeated studies, the present inventors have found that a compound in which a specific substituent is added to an indolenine cyanine dye can achieve the above object.
[0017]
The present invention has been made on the basis of the above knowledge, and comprises an optical recording material comprising a compound represented by the following general formula (I): It is to provide.
[0018]
[Chemical 2]

(In the formula, n represents an integer of 1 to 3, m represents an integer of 0 or 1, 6-membered ring A represents a benzene ring or a cyclohexane ring, and X represents an alkylene group having 1 to 3 carbon atoms. , An ⁻ represents an anion, and when m is 0, R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an alkenyl group or an alkenyloxy group. And when m is 1, R ₁ represents a halogen atom or an alkoxy or alkenyloxy group having 1 to 8 carbon atoms, and R ₂ represents a hydrogen atom, a halogen atom or an alkoxy group or alkenyl having 1 to 8 carbon atoms. Represents an oxy group, except that when n is 1 and m is 1, R ₁ or R ₂ is a halogen atom.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical recording material of the present invention will be described in more detail.
[0020]
The compound represented by the general formula (I) according to the present invention is a dye used for the recording layer of an optical recording medium.
[0021]
In the compound represented by the general formula (I), examples of the alkyl group having 1 to 8 carbon atoms represented by R ₁ and R ₂ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, Tert-butyl, isobutyl, amyl, tert-amyl, hexyl, heptyl, octyl, isooctyl, tert-octyl, 2-ethylhexyl, etc. are mentioned. The alkoxy group having 1 to 8 carbon atoms is derived from the above alkyl group. Examples of the alkenyl group having 1 to 8 carbon atoms include vinyl, propenyl, isopropenyl, butenyl and the like, and examples of the alkenyloxy group having 1 to 8 carbon atoms include the above alkenyl groups. Examples include a group to be derived, and examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.
Moreover, as a C1-C3 alkylene group represented by X, a methylene, ethylene, trimethylene, etc. are mentioned, for example.
[0022]
Examples of the anion represented by An ⁻ include halogen anions such as chlorine anion, bromine anion, iodine anion, and fluorine anion; perchlorate anion, thiocyanate anion, phosphorus hexafluoride anion, and antimony hexafluoride anion. , Inorganic anions such as boron tetrafluoride anion, or organic sulfonate anions such as benzenesulfonate anion, toluenesulfonate anion, trifluoromethanesulfonate anion; octyl phosphate anion, dodecyl phosphate anion, octadecyl phosphate anion, An organic anion such as an organic phosphate anion such as phenyl phosphate anion and nonylphenyl phosphate anion, or an anion as described in JP-A-60-234892, for example, as a quencher anion. Emissions, and the like. Representative examples of the quencher anion include anions represented by the following general formulas (A) and (B):
[0023]
[Chemical 3]

[0024]
In addition, n represents an integer of 1 to 3, and a compound in which n is 1 is particularly preferable because it has excellent sensitivity to writing and reproducing wavelengths of 620 to 690 nm.
[0025]
Among the compounds represented by the general formula (I), in particular, a compound in which at least one of R ₁ and R ₂ is a halogen atom, a compound in which at least one of R ₁ and R ₂ is an alkoxy group, or R ₁ and A compound in which at least one of R ₂ is an alkenyloxy group is preferred.
[0026]
As typical examples of the compound represented by the general formula (I), the following compound No. 1-5 etc. are mentioned . In the illustrated below, it shows cyanine dye cation omitting anions. Of the following compounds, Compound No. 4 is a reference compound.
[0027]
[Formula 4]

[0028]
[Chemical formula 5]

[0029]
[Chemical 6]

[0030]
[Chemical 7]

[0031]
[Chemical 8]

[0032]
The optical recording material of the present invention comprising the compound represented by the general formula (I) is a salt of the cyanine dye cation and anion and can be produced according to a conventionally known method.
[0033]
Next, specific synthesis examples of the compound represented by the general formula (I) will be given.
[0034]
(Synthesis Example 1) Compound No. 1 4-hydroxyphenethyl alcohol 48.4 g, KOH 39.3 g, and ethanol 78.9 g were charged into a round bottom 500 ml flask with a perchlorate synthesis thermometer, condenser, and nitrogen inlet tube, and heated to 70 ° C. . Thereto, 46.6 g of allyl bromide was added dropwise over 90 minutes, and then reacted at 80 ° C. for 1 hour. After cooling, the solvent was distilled off, the residue was dissolved in 200 ml of toluene, and water washing and oil-water separation were repeated 4 times with 200 ml of water. The organic layer was taken and the solvent was distilled off to obtain 41.6 g (colorless transparent liquid, yield 66.8%) of 4-allyloxyphenethyl alcohol as the first intermediate.
[0035]
The obtained 4-allyloxyphenethyl alcohol (26.7 g) and pyridine (29.7 g) were charged, and 26.5 g of benzenesulfonic acid chloride was added dropwise with stirring at 0 to 10 ° C. The mixture was stirred at this temperature for 1 hour and further stirred at room temperature for 1 hour. Next, 100 ml of chloroform was added and dissolved, and the mixture was washed twice with 100 ml of water and separated into oil and water. The organic layer was taken and the solvent was distilled off to obtain 40.5 g (colorless transparent liquid, yield 84.7%) of 4-allyloxyphenethylbenzenesulfonate as the second intermediate.
[0036]
15.9 g of the resulting 4-allyloxyphenethylbenzenesulfonate and 5.1 g of 2,3,3-trimethyl-5-nitroindolenine were charged and reacted at 135 to 140 ° C. for 1 hour to obtain a third intermediate 1 A benzenesulfonate salt of-(4'-allyloxyphenethyl) -2,3,3-trimethyl-5-nitroindolenine was obtained. This reaction was used directly in the next step without purification.
[0037]
The above reaction product, 0.73 g of N, N-diphenylformamide, 11.9 g of pyridine and 1.9 g of acetic anhydride were charged and reacted at 115 ° C. for 1 hour. Next, 3.9 g of sodium perchlorate monohydrate and 19.3 g of methanol were added and reacted for 1 hour under methanol reflux. After the solvent was distilled off, recrystallization was performed from a mixed solvent of DMF / methanol = 1/3. 1 g of 2.5 perchlorate (green crystals) was obtained.
[0038]
The following results were obtained as optical characteristics of the obtained crystals.
・ Λmax (chloroform solution, the same shall apply hereinafter) = 587.0 nm
· Epsilon (molar extinction coefficient at .lambda.max, hereinafter the same) = 2.04 × 10 ⁵
[0039]
Similar to the above (Synthesis Example 1), Compound No. Two to five perchlorates were synthesized and λmax and ε were measured for each compound. The results are shown in [Table 1] below.
[0040]
[Table 1]

[0041]
The optical recording material of the present invention is applied as a recording layer of an optical recording medium. Thereby, the optical recording medium which formed the thin film which consists of a compound represented with the said general formula (I) on a base | substrate can be provided.
For forming the optical recording medium, a conventionally known method can be used. In general, lower alcohols such as methanol and ethanol, ether alcohols such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and butyl diglycol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and diacetone alcohol, ethyl acetate , Esters such as butyl acetate and methoxyethyl acetate, acrylic esters such as ethyl acrylate and butyl acrylate, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol, benzene, toluene, xylene, etc. Optically easily by applying a solution of the optical recording material of the present invention on a substrate in an organic solvent such as chlorinated hydrocarbons such as hydrocarbons, methylene dichloride, dichloroethane, chloroform, etc. It is possible to form a recording medium.
[0042]
The thickness of the recording layer is usually 0.001 to 10 [mu], preferably 0.01 to 5 [mu]. The method for forming the recording layer is not particularly limited, and a commonly used method such as a spin coating method can be used.
[0043]
When the optical recording material of the present invention is contained in the recording layer of the optical recording medium, the amount used with respect to the recording layer is preferably 50 to 100% by weight.
[0044]
In addition to the optical recording material of the present invention, the recording layer may contain resins such as polyethylene, polyester, polystyrene, and polycarbonate, if necessary, a surfactant, an antistatic agent, a lubricant, You may contain a flame retardant, a stabilizer, a dispersing agent, antioxidant, a crosslinking agent, etc.
[0045]
Further, the recording layer may contain an aromatic nitroso compound, a transition metal chelate compound or the like as a quencher such as singlet oxygen. As these compounds, for example, known compounds as proposed in JP-A-59-55795 are used. The compound is preferably used in the range of 0 to 50% by weight based on the recording layer.
[0046]
The material of the substrate on which such a recording layer is formed is not particularly limited as long as it is substantially transparent to writing light and reading light. For example, a resin such as polymethyl methacrylate, polyethylene terephthalate, and polycarbonate is used. Glass or the like is used. Moreover, the shape can use arbitrary shapes, such as a tape, a drum, a belt, a disk, according to a use.
[0047]
In addition, a reflective film can be formed on the recording layer by vapor deposition or sputtering using gold, silver, aluminum, copper or the like, or a protective layer made of acrylic resin, ultraviolet curable resin, or the like. You can also.
[0048]
The optical recording material of the present invention can be used as a dye for optical disks such as LD, CD, DVD, CD-R, and DVD-R, and is particularly suitable for DVD-R that uses light having a wavelength of 620 to 690 nm for writing and reproduction. Is preferred.
[0049]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples. Of the following examples, Examples 1-4, 2-4, and 3-4 are reference examples.
[0050]
Example 1
On a 12 cm diameter polycarbonate disk substrate coated with a titanium chelate compound (T-50: manufactured by Nippon Soda Co., Ltd.) and hydrolyzed to provide a base layer (0.01 μm), the dyes and aromatics shown in Table 1 below A 1: 0.1 (weight ratio) ethyl cellosolve solution of a nitroso compound (DQ-24: manufactured by Asahi Denka Kogyo Co., Ltd.) was applied by a spin coating method to form a recording layer having a thickness of 100 nm.
[0051]
Further, a 100 nm gold reflective film was formed on the recording layer by vapor deposition.
[0052]
Writing was performed from the back side of the substrate using a semiconductor laser (635 nm, condensing unit output 7 mW, frequency 2 kHz) while rotating each optical recording medium thus prepared at 3.6 m / s.
[0053]
Next, a semiconductor laser (650 nm, condensing unit output 0.1 mW) was used as readout light, reflected light through the substrate was detected, and the C / N ratio was measured with a spectrum analyzer at a bandwidth of 30 kHz.
[0054]
Also, the back surface of the substrate after 0.1 mW laser as readout light, 1 μsec wide, 3 kHz pulse after irradiation for 5 minutes in a static state and after storage for 2500 hours at 40 ° C. and 88% relative humidity The change (%) in reflectance from the side was measured. The results are shown in [Table 2] below.
[0055]
[Table 2]

[0056]
[Chemical 9]

[0057]
[Chemical Formula 10]

[0058]
(Example 2)
Each optical recording medium was prepared in the same manner as in Example 1 using the dyes shown in Table 3 below, and the refractive index (n) and extinction were measured using a spectroscopic ellipsometer (M-150, manufactured by JASCO Corporation). The coefficient (k) was measured. The results are shown in [Table 3] below.
[0059]
[Table 3]

[0060]
(Example 3)
Each medium was prepared in the same manner as in Example 1 using the dyes shown in Table 4 below, and light of 50000 lux was emitted using a xenon weather resistance tester (Table Sun, manufactured by Suga Test Instruments Co., Ltd.). After irradiation, the absorbance half-life at λmax (the time required for the absorbance value at λmax to decrease to 50% at the time of preparation of the medium) was measured. The results are shown in [Table 4] below.
[0061]
[Table 4]

[0062]
As is clear from the above examples, when the compound represented by the general formula (I) according to the present invention is used, the writing sensitivity is excellent compared with the case where a conventional cyanine dye is used, and the irradiation is performed. Since the decrease in reflectance after and after storage is extremely small and the balance between n and k is excellent, extremely reliable recording is possible.
[0063]
【The invention's effect】
The optical recording material of the present invention has good light stability, storage stability and solubility in a solvent, and has high sensitivity.

Claims (4)

An optical recording material comprising a compound represented by the following general formula (I):

(In the formula, n represents an integer of 1 to 3, m represents an integer of 0 or 1, 6-membered ring A represents a benzene ring or a cyclohexane ring, and X represents an alkylene group having 1 to 3 carbon atoms. , An ⁻ represents an anion, and when m is 0, R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an alkenyl group or an alkenyloxy group. And when m is 1, R ₁ represents a halogen atom or an alkoxy or alkenyloxy group having 1 to 8 carbon atoms, and R ₂ represents a hydrogen atom, a halogen atom or an alkoxy group or alkenyl having 1 to 8 carbon atoms. Represents an oxy group, except that when n is 1 and m is 1, R ₁ or R ₂ is a halogen atom. The optical recording material according to claim ₁ , wherein in the general formula (I), at least one of R ₁ and R ₂ is an alkoxy group. _2. The optical recording material according to claim 1, wherein in the general formula (I), at least one of R ₁ and R ₂ is an alkenyloxy group. An optical recording medium, wherein a thin film made of the compound represented by the general formula (I) is formed on a substrate.